Evolution and nucleosynthesis of AGB stars

DOI

We present stellar evolutionary tracks and nucleosynthetic predictions for a grid of stellar models of low- and intermediate-mass asymptotic giant branch (AGB) stars at Z=0.001 ([Fe/H]=-1.2). The models cover an initial mass range from 1 M_{sun} to 7 M{sun}. Final surface abundances and stellar yields are calculated for all elements from hydrogen to bismuth as well as isotopes up to the iron group. We present the first study of neutron-capture nucleosynthesis in intermediate-mass AGB models, including a super-AGB model, of [Fe/H]=-1.2. We examine in detail a low-mass AGB model of 2 M{sun} where the ^13^C({alpha},n)^16^O reaction is the main source of neutrons. We also examine an intermediate-mass AGB model of 5 M{sun} where intershell temperatures are high enough to activate the ^22^Ne neutron source, which produces high neutron densities up to ~10^14^ n/cm^3^. Hot bottom burning is activated in models with M>=3 M{sun}. With the 3 M{sun}_ model, we investigate the effect of varying the extent in mass of the region where protons are mixed from the envelope into the intershell at the deepest extent of each third dredge-up. We compare the results of the low-mass models to three post-AGB stars with a metallicity of [Fe/H]~-1.2. The composition is a good match to the predicted neutron-capture abundances except for Pb and we confirm that the observed Pb abundances are lower than what is calculated by AGB models.

Identifier
DOI http://doi.org/10.26093/cds/vizier.17970044
Source https://dc.g-vo.org/rr/q/lp/custom/CDS.VizieR/J/ApJ/797/44
Related Identifier https://cdsarc.cds.unistra.fr/viz-bin/cat/J/ApJ/797/44
Related Identifier http://vizier.cds.unistra.fr/viz-bin/VizieR-2?-source=J/ApJ/797/44
Metadata Access http://dc.g-vo.org/rr/q/pmh/pubreg.xml?verb=GetRecord&metadataPrefix=oai_b2find&identifier=ivo://CDS.VizieR/J/ApJ/797/44
Provenance
Creator Fishlock C.K.; Karakas A.I.; Lugaro M.; Yong D.
Publisher CDS
Publication Year 2017
Rights https://cds.unistra.fr/vizier-org/licences_vizier.html
OpenAccess true
Contact CDS support team <cds-question(at)unistra.fr>
Representation
Resource Type Dataset; AstroObjects
Discipline Astrophysics and Astronomy; Interdisciplinary Astronomy; Natural Sciences; Observational Astronomy; Physics; Stellar Astronomy